Groundhog Day

Living in central Pennsylvania, it would seem remiss of me not to comment on Groundhog Day today. For those not familiar with the event, Groundhog Day, which takes place on February 2 every year, is the modern American version of an age-old tradition originating in Europe centuries ago. The modern Groundhog Day is celebrated in the United States in Punksutawney Pennsylvania (about 100 miles west of Penn State University, where I teach). According to legend, if the groundhog–who is named Punxsutawney Phil–sees his shadow, there will be six more weeks of winter weather. If he does not see his shadow, there will be an early spring. After Phil emerges from his burrow on February 2, he speaks to an event official in “Groundhogese”, and his prediction is then translated for the awaiting public. The event was popularized in the 1993 movie of the same name, starring Bill Murray.

Sadly, it appears that global warming may soon add Phil to the ranks of the unemployed. With the warming of 4-8ºC (7-14ºF) predicted over North America by the end of this century if we continue to increase greenhouse gas concentrations at current rates, the answer will become simple. Spring will come early every year. While this may seem like a pleasant outcome of climate change, it could in fact lead to serious problems for plants, animals, and entire ecosystems. Living things have adapted to the timing of the seasons over many thousands of years. Here, we are changing the timing of the seasons on timescales of decades. Plants and animals just don’t adapt well to changes on such short timescales.

January temperatures this year were 3-9ºC (5-16 ºF) warmer than the late 20th century average over most of the U.S. (see Figure).

Departure of January ’06 surface air temperatures from the late 20th century (1971-2000) average [source: NOAA Climate Prediction Center] (click to enlarge)

The widespread pattern of this warmth is what was so unusual. Usually when one part of the U.S., say the east coast, is experiencing unusually warm weather, other regions, say the Rocky Mountain states, are experiencing unusually cold weather. This has to do with the natural wiggles of the jet stream from one month to the next. However, the pattern we’re seeing so far this year, where essentially the entire U.S. is anomalously warm, only occurs when the jet stream has retreated far north from its usual position. As we have noted before (see here and here), there is no way to ascribe any single anomalous weather event, or even an anomalous season, to global warming and climate change. But what we can say is that the temperature pattern we’ve seen this January is similar to the kind of pattern that models predict as being normal in just a few decades time given some anthropogenic forcing scenarios. Global warming is likely to “load the dice”, making the kind of January temperatures that might seem remarkable by past experience increasingly probable, and hence increasingly more frequent.

In the movie Groundhog Day, Bill Murray’s character finds himself having to repeat the same day over and over again (Groundhog Day, of course). At one point he announces “It’s cold today, it’s cold every day”. Were the movie to be remade several decades in the future, the character might instead have to lament: “It’s warm this winter, it’s warm every winter”.

82 Responses to “Groundhog Day”

Many of the weather reporters/forecasters on The Weather Channel are talking up the fact that January temps this year are far above normal. I have not heard any mention of GW or Climate Change but many of the millions of Americans who watch The Weather Channel must be wondering why this is happening.

On the other hand, we’ve had a cool winter in the uk this year, with much colder weather in eastern europe.

I thought this was due to variations in the north atlantic oscillation. Would this system lead to warmer n.america?

[Response:While it has been cold in Central Europe, Scandinavia – which perhaps bears the brunt of the NAO – has been very mild indeed. There have been 8 (high) temperature records in January (text in Norwegian) in the northernmost part of Norway, as well as a flooding disaster in mid-Norway in end of January with record high rain (not snow!) fall in 29 locations. On the other hand, there have been reports of snow in Portugal (near the southern pole of the NAO dipole). These events are associated with the meandering of weather fronts as well as low-or-high pressure systems. The January 2006 SLP anomaly indicates high pressure over Fennoscandia and northwestern Russia, rather than over Iceland – hence it does not seem as the NAO was particularly weak for January. -rasmus]

Come on guys, there should be at least some QA/QC that goes on at Real Climate concerning the stuff you all write. You all aren’t being internally consistent.

For instance, Gavin has just spent the last few days defending the work that comes out GISS and then Mike writes the following:

“Sadly, it appears that global warming may soon add Phil to the ranks of the unemployed. With the warming of 4-8ºC (7-14ºF) predicted over North America by the end of this century if we continue to increase greenhouse gas concentrations at current rates, the answer will become simple.”

Yet slide 43 of Hansen’s AGU talk shows that the “current rate” of greenhouse gas increase lies beneath all IPCC SRES scenarios (including A2 that Mike linked to), and instead falls somewhere between Hansen’s “alternative scenario” and his “2ºC scenario.” Now, to see what this means for temperatures over North America by the end of this century, I direct you to the transient simulations from the GISS ModelE web page (I think that Gavin would agree that this would be a reasonable place to go) http://data.giss.nasa.gov/modelE/transient/. One there, go down to Table 5 “Future Scenarios” and create lat-lon plots of surface temperature trends for the 21st century (or anomalies at the end of the century vs. the beginning) using any of the “GISS scenarios.” You will find that the temperature change over North America is barely HALF of what Mike suggests it will be.

Why is it so necessary to exaggerate or use the results from unrealistic scenarios? Just tell it like it is, using the best available science and let folks decide what to make of things. Mike’s story can still be told using a potential temperature rise of 1.5-3ºC across North America, so why not tell it that way?

[Response: A better phrasing would have been ‘up to 4-7 deg C’. We don’t have an agreed upon probability distribution function for the different scenarios, so picking one over another and not taking into account the uncertainty in climate sensitivity (the GISS model being on the lower end this time around) is not right either. A range is approporiate though. – gavin]

My complaint isn’t very substantial, but my training is in biology so if I’m ever going to comment on this blog it might as well be now.

You say, “Here, we are changing the timing of the seasons on timescales of decades. Plants and animals just don’t adapt well to changes on such short timescales.” This is somewhat untrue. A lot of it depends on the generation times of the plants and animals involved. Plants and beasts with shorter generation times are generally quicker to adapt. More important is the amount of additive genetic variation present for natural selection to act upon in the populations of those critters. Because many of the species are organised in semi-isolated subpopulations that experience different climates already, the species as a whole have a great wealth of genetic diversity for selection to act upon. Within many species, where we’ve looked, the great variation in success (fitness) year-to-year among body types (e.g., Darwin’s Finches) or life history types (e.g., shore-spawning versus river-spawning sockeye salmon) tells us that even species with fairly slow reproduction can respond rapidly to a changing environment (including “speciation” within 13 generations for sockeye [4-year generation time] according to Andrew Hendry).

However! Different species will respond in different ways to the directional change in climate and they will be differentially successful. Some species will move and/or evolve faster than others. That means that I agree completely with your assertion that ecosystems will be greatly altered — the interactions among species will be radically changed, some species will not keep up and will be lost from the ecosystems while other species will invade from other ecosystems.

Superficially, things might not look too different (bark beetles and wildfires notwithstanding). There will be creatures living pretty much everywhere they currently live. The total amount of primary production might not decrease; it may even increase. To folks predisposed to downplay the effects of climate change on ecosystems, the changes that will occur will not be seen very negatively. In fact, at a superficial level, future development (paving) will probably have a much more obvious impact for the average person (who wouldn’t have any recollection of how their surrounding ecosystem used to function). That’s something to keep in mind.

[I made similar comments on the acidification of the ocean post a few months ago — my turn to play Bill Murray I guess]

Thanks for that informative comment! I was wondering if you know some good resources that deal with climate change from a purely biological but still broad perspective. I understand and accept your points but it seems to me that history (eg PETM) does provide evidence that if a change is large enough and sudden enough the net effect can be extremely detrimental to the biosphere, at least on timescales humans are accustomed to thinking about.

These things must be very difficult to quantify. Are you aware some work that tries to do that?

Also, in terms of adaptation I think another very important concern is that climat change is not the only hit that ecosystems have taken, are taking and will take. Over-exploitation and general pollution will reduce that chance that a healthy population or ecosystem might have otherwise had.

I’m new to some of the global warming science, though I have a science background and I’ve been reading. I’m hoping someone can clear something up for me.

Our atmospheric co2 levels are at 380, up from a preindustrial level of 280. Other trace global warming pollutants (GWP) including methane are higher, too. These levels are likely to persist for hundreds of years. The supposition is that our average global temps have risen 1 deg F in the past 100 or so yrs as a result of these GWPs.

This 1 deg F increase has caused significant retreat of glaciers around the world, as well as polar ice sheets. My understanding is that the western ice sheet at one of the poles and the Greenland ice sheet are both considered “unstable”.

Even if humans could hypothetically stop all GWP today, we would have a persistant state of high GWPs in the atmosphere, which would continue to increase the average global temp, and continue to melt glaciers and polar ice.

Even if we were to follow Gore’s advice and construct massive CO2 filter/fixing plants and scrub the atmosphere down to preindustrial GWP levels, aren’t we still subject to the positive feedback loop defined by the relative albedos of snow/ice and water? Significantly more solar energy is being absorbed by sea water and exposed landmass by virtue of having less ice, causing greater release of methane and co2 from thawed peat.

I’m hoping I have something wrong here, or I’m missing something. Because by this reasoning it seems doubtful human intervention, whether it be legislating tailpipe emission standards, shutting down our entire power grid and all vehicles today, or even constructing co2 fixing factories, could stop Earth’s demise.

I accept that greenhouse gases affect the climate, and that they should be reduced, but I do have some questions about your post:

1. You write that current temperature anomalies are consistent with “some anthropogenic forcing scenarios.” Yes, but it is 2006 and the scenario that you have selected is for 2021-2050. So does this mean that the current temperature anomaly is inconsistent with IPCC scenarios?http://www.grida.no/climate/ipcc_tar/wg1/351.htm

2. Further the A2 scenario that you have chosen does not reflect present (or cumulative) emissions or population, so again, does this mean that because current patterns match this scenario that it is (a) just a coincidence, or (b) evidence of inconsistency between observations and this scenario? Isn’t there a more scientifically robust way to assert attribution in such cases (a la Myles Allen et al.)?

Isn’t it the case that most any pattern of warmer than average weather would be “consistent with” one or other of these scenarios? Should I then interpret this to mean that the anomalously cold pattern recently in Easter Europe are evience of inconsistency with the various IPCC scenarios, as I don’t see any of the IPCC scenarios that match? Is it that confirming evidence is accepted, and disconfiming rejected? How should I sort this out?

Thanks for your answers!

[Response: If I can answer for Mike, it is clear that he’s saying that this kind of pattern is something that resembles patterns that may become more frequent under the various scenarios. It’s not an attribution study, and he is not asserting that this anomaly is associated with climate change. Mike nowhere states that this is ‘consistent with’ projections and specifcially states that anomalous months (whether in the US or in Europe) are not attributable to climate change. Thus this is neither confirming nor refuting anything. It’s just an example. -gavin]

#8, re biota with shorter generation times — I’m thinking bacteria & viruses. Who knows what new microscopic, unseen demons will evolve in a changing climate. Experts are talking about known diseases spreading to new areas in a warming climate, but what about the unknown ones (because they haven’t evolved or adapted yet). Boo! I think I just saw my own shadow.

On another note, I loved GROUNDHOG DAY, because it shows a person given more and more chances to get it right, and progression from a cynical, nasty person to a good, charitable person. I keep hoping the contrarians will make the same progress, open their hearts, and start reducing their GHGs (at least just to humor the rest of us). Only problem is we may not have an infinite number of chances to get it right.

As for now I’m enjoying winter here in the 26th latitude N — I love the 70s & 80s (the highs have been close to 90 this week). I hardly even think about summer, which under normal conditions can sometimes get to 112 degrees. And what about others who live in really hot climates?

Perhaps naive question — have the infrared astronomers measured a change in how much IR gets through the atmosphere? (Can we review for example old astronomical survey photographic plates, knowing how those emulsions reacted to IR wavelengths, seeing what stars appear and at what magnitudes, and look at them again today and see if those (red dwarf stars, I suppose) are relatively less bright through the current atmosphere?

Or can direct measurements — for example pointing an infrared laser at an infrared-detecting satellite — be done regularly for a few years and any change seen that matches the annual variation and average increase in CO2?

Re #10, even if we’ve reached the tipping point (I don’t think anyone knows for sure when that will be reached, or if it has been already), we still need to do all we can to reduce GHGs so as to lessen the harm, esp for future generations.

It may already be slated to get very bad, but we don’t have to make it still worse. And in that scenario, every tiny bit we can reduce will be like putting drops of water on a thirsting man’s tongue & be received as the greatest relief, much more than givng a rich man a second yacht.

I have a problem with this Eastern Europe cold wave publicity, anomaly maps are hard to find for that region. Any links available before Gisstemp comes out? AO proponents must be scratching their heads, seems like the Pacific is providing a great deal of heat and moisture. Extraordinary warmer January has something to do with warmer air all the way to the Pole causing the jet stream to position itself accordingly, not like the jet stream goes wherever it wants to, but rather it places itself at the border between Polar and Continental air masses, where there is a significant drop in tropopause, if the Artic air mass is shrunken the jet stream heads Nortwards.

[Response:There are some maps on CPC where you can see weekly anomalies for Europe – just click on the map (the monthly anomaly for January is not yet available but I guess it’s coming soon). -rasmus]

If the link below is too controversial, please remove it, editors. I thought some might like it. And afterall science, politics, and economics are pretty much tied in together, like it or not (though I expect honest scientists to keep on striving for objectivity & honesty).

Michel Foucault (social scientist) said, “Power is knowledge” (but I don’t think even he knew how true that statement was).

Thanks for your response in #7, but you only addressed part of my concern. Mike claimed his 4-8ºC rise “if we continue to increase greenhouse gas concentrations at current rates”. Yet clearly Jim Hansen, as I pointed out, shows that the “current rate” of greenhouse gas forcing is less than IPCC SRES A2 (the scenario linked my Mike), and in fact is less than all the IPCC SRES scenarios. Admittedly, perhaps it won’t stay that way in the future, but, unless you are denying Hansen’s results, it definitely isn’t now. So, perhaps the sentence should have read something more along the lines of:

“With a warming projected to be somewhere between 1.5-8ºC (3-14ºF) over North America by the end of this century under various scenarios of future greenhouse emissions, the answer will become simple.”

This, I think, is a more fair representation of the science -which is after all, is one of the primary goals of Real Climate is it not?

Note in the link from #16 that the Arctic regions above eastern Europe and Siberia are anomalously warm by about the same amount, and that (based purely on a visual inspection) the global average will probably be fairly close to zero. I’ve heard it said with some frequency that we can expect more climate instability of this sort as global warming progresses, but is this type of behavior by the jet stream a big part of what is meant by that?

[Response: I don’t think so. The wiggley-ness of the jet stream is associated with the phase of the NAO/AO – when the phase is negative, there is more variability (Thompson and Wallace, 2001), and when it’s postive, less. Since the projections are for a strengthening NAO (more positive phase), then that would indicate less jet stream variability in future. However, this is not an absolutely robust result and so while I’d rate it as ‘more likely than not’, it’s not with very much confidence. – gavin]

“Spring will come early every year. While this may seem like a pleasant outcome of climate change, it could in fact lead to serious problems for plants, animals, and entire ecosystems. Living things have adapted to the timing of the seasons over many thousands of years. Here, we are changing the timing of the seasons on timescales of decades. Plants and animals just don’t adapt well to changes on such short timescales.”

“What are the words used by indigenous peoples in the Arctic for “hornet,” “robin,” “elk,” “barn owl” or “salmon?” If you don’t know, you’re not alone. Many indigenous languages have no words for legions of new animals, insects and plants advancing north as global warming thaws the polar ice and lets forests creep over tundra.”

Earth is becoming a greener greenhousehttp://cliveg.bu.edu/greenergh/nontechsum.html
“Our results … indicate that the April to October average greenness level increased by about 8% in North America and 12% in Eurasia during the period 1981 to 1999.”
“the growing season is now about 12 Â± 5 days longer in North America and 18 Â± 4 days in Eurasia”

Greening of arctic Alaska, 1981-2001http://www.agu.org/pubs/crossref/2003/2003GL018268.shtml
“Here we analyzed a time series of 21-yr satellite data for three bioclimate subzones in northern Alaska and confirmed a long-term trend of increase in vegetation greenness for the Alaskan tundra that has been detected globally for the northern latitudes.”

“… species … are now disappearing at the rate somewhere of a thousand times faster than they are born due to human activity. At this rate, in one human lifetime, we can easily eliminate half the species of the world. Many of these have developed over thousands or millions of years. The clearly demarcated species that can be tracked in the fossil record, before humanity originated, appeared roughly on the order of about one species per million per year. Any rapid process of speciation that would let them begin again can’t duplicate that.”

nanny, scale is very important in assessing ecosystems. Short-term increases in NPP are not necessarily permanent. What is more important is the rate of adaptation for spp. that are in areas that are changing. What may be best for you to understand this concept is to trace the historical range of Sequoia sempervirens for west coast glaciation range changes, and Castanea dentata on the east coast. As canopy cover is an important component of ecosystem diversity, it is important to understand how quickly these representative species (in the fossil record) can change their range.

Most non-Googlers are far more sanguine about these changes than, say, folk who do this for a living [like ecologists as in comment #21 EO Wilson] – the changes being unprecedented in nonglacial times and with the also recent unprecedented CO2 levels, there is, simply, nothing in the past on which to base happyhappy touts.

#21: From your link it appears that deforrestation of tropical areas, and pollution and drainage of freshwater systems are blamed for the disappearance of species. What do these have to do with Global Warming?

Also from your link:

“ActionBioscience.org: How quickly can these and other mechanisms produce new species?

Wilson: Instantly. Well, in a few generations. First of all, in plants, there’s a mechanism — called polyploidy — which, in one step, can create a strain that can’t breed with the original stock from which it came. In fact, it’s called instantaneous speciation.”

Like this? “giraffes find themselves in a changing environment in which they can only survive by eating leaves high up on trees. So, they stretch their necks to reach the leaves and this stretching and the desire to stretch gets passed on to later generations. As a result, a species of animal which originally had short necks evolved into a species with long necks.”

Yeah, Nanny, you’re off base here. The instantaneous speciation that occurs in some plants just doubles the amount of DNA in each cell. These polyploids typically have larger cells and larger bodies than the parental species. But it is only a rare lucky coincidence that they will find themselves in an environment in which they are fitter than the parental species. It happens, but I don’t think that there’s any physiological reason to believe that these mutants will be favored on a warmer planet. On the other hand there are plenty of reasons to believe that polar bears and ringed seals won’t do well. Their ‘functions’ in the Arctic ecosystem will be replaced by other creatures to some extent, but evolution won’t prevent their loss.

You said:
“Their ‘functions’ in the Arctic ecosystem will be replaced by other creatures to some extent, but evolution won’t prevent their loss.”

Even in your doom and gloom scenario, won’t the two species (polar bears and seals) be replaced by many many species in a warmer, wetter world? Wouldn’t you consider sacrificing one species if it meant that many more could thrive, or is this the “Star Trek II: Search for Spock” version of enviromentalism where “the needs of one outweigh the needs of many”?

My wife and I take a trip each year to celebrate our anniversay (mid-January). Wherever we’ve gone recently has seen record or near record cold for the time. New York 2 years ago hit all time lows, I think, and we just returned from Barcelona where all the locals we spoke with about the cold and wet were very apologetic. Our 60 year old driver claimed to have never seen similar weather.

There’s a film titled The Cooler about a sad sack who brings bad luck to gamblers on a hot streak. GW sceptics should study us and see if we’re the possible contrary forcing that they’ve been looking for: The Coolers.

To answer briefly, no, I am ignorant of paleoecology and don’t know any good references. I wish I did. My comments reflect a population genetics perspective.

Now a more lengthly answer about something I know very little about.

Definitely really fast/dramatic changes will have terrible outcomes for the organisms most affected, whether that change is precipitated by an asteroid impact or whatever it was that triggered the PETM. I don’t think what we’re talking about here is as significant as the PETM, though, at least in terms of model predictions. But even with the PETM I think you may find examples in support of my earlier post (now #8): some of the best data on biotic changes during PETM come from foraminifera, right? Well, those are little protists good at fossilizing. The same thing that makes them good at fossilizing may have made them particularly vulnerable. Could their ‘function’ in an ecosystem be replaced by other critters? How about diatoms? I saw a paper about turnover of diatoms near that period by wasn’t able to read the abstract.

But focus on the idea of turnover. Changes in climate will manifest themselves as changes in local environments. Some species of diatoms which dominated prior to the enormous PETM changes probably didn’t adapt well, and you could probably say the same thing about most of the rare species, but a few species that were somehow pre-adapted for the climate change probably thrived after being released from the competitive effects of the other species. They might not have filled the niches so completely that they could replace 100% of the primary productivity provided by the full biodiversity of diatoms (and other algae) prior to the PETM, but I don’t think we can assume that the oceans became barren (despite their toxicity to most species). I have no evidence but would be happy to be educated on the matter.

So, to repeat myself, I think the composition of ecosystems will change although at a superficial level their ‘output’ won’t change very much. We’ll see changes from yesterday’s fairly diverse ecosystems to tomorrow’s monocultures in the areas most affected. This actually brings up Lynn’s point (now #12) about disease organisms, although in a different way (I’m not that worried about scary new things evolving) — monocultures are more succeptible to disease outbreaks. Thus, a new prediction: we’ll see more boom and bust with the loss of diversity. (Actually not such a new idea.)

Ah, Nanny, but I believe that even Mitch Taylor would agree that when the sea ice gets really rare the ringed seals will have no place to pup and the polar bears will have diddly to eat except garbage. I’ll keep an eye out for future work done on the issue, though, and thanks for the link.

I shouldn’t do this, but let’s talk about ethics just for a brief moment. You’re saying that we should change the earth faster to reduce barriers to new speciation? Are we talking about the needs of potential species? It’s interesting, but keeping with your anthropomorphic framing via the Star Trek utilitarianism, isn’t this a little like asking if we should steal the gametes of male and female humans who have chosen not to mate so that we can fulfil the needs of their unborn children to be conceived? (My apologies to the moderators who want to keep this to science.)

“Regardless, the levels of Ba and P recorded across the P/E boundary at Sites 1220 and 1221 are high in comparison to those measured in other Leg 199 sediments. This observation, together with the congruency of behavior between the two elements, raises the intriguing possibility that the shipboard data record an increase in surface ocean productivity across this important paleoceanographic interval (Thomas et al., 2000; Bains et al., 2000) rather than an increase in barite saturation arising from the injection of Ba into the global ocean from the marine gas hydrate reservoir (Dickens, 2001).”

The website is from 2002. Perhaps this question has been resolved already?

So, speaking of whether or not to come out of one’s hole or go back and hibernate, did everyone see today’s Wall Street Journal front page article about contention among hurricane researchers? It’s the catty side of the WSJ, more heat than light I suspect.

Nanny, it seems to me that if you are really concerned about government intervention in the lives of citizens, then you should jealously guard the circumstances that allow political stability. Severe economic dislocations always increase the risk of dictatorship, whether of the right (as in Germany after the disasters of the Weimar period) or the left (as in Russia during the devastation of WWI.) It is possible that global warming will turn out to be less dangerous than some scientists predict. But it is, frankly, much more probable that the consequences will result in massive economic disruption. We have a chance now to take action to lessen that risk. Waiting only increases the role government will have to play to manage this disruption. What are conservatives, of all people, waiting for? It’s time to stop denying an unpleasant reality and start offering ideas for solutions. For example, here is an argument presented by an economist on the difficulties and prospects for using market forces to address global warming (from private correspondence):

There is no market for the atmospheric chemistry even though it is a precious resource. This is what economists call a “missing market” or an “externality.” People can alter the atmospheric chemistry in a way that degrades its social value without having to pay anything for it. In this situation, economic actors acting as individuals will use such a precious source as if the price were zero even though the true social value is quite high.

The problem with the market for atmospheric chemistry is that we can’t meaningfully establish property rights over its use. As a consequence, there is no agent sitting there charging people everytime they make use of the atmoshpere.

The end result is that we end up using the atmosphere as a carbon dump instead of a mechanism for protecting human life.
This is the case even though we have reached the point at which the atmospheric chemistry has far greater marginal value protecting us from the sun than it does as a carbon sink.

If there were some economic actor making the people who want to use the atmosphere as a carbon sink compete against the people who want to use it as a optimally configured blanket around the planet, the people looking for a carbon sink would
find another option.

Economists have spent a lot of time trying to come up with strategies that would mimic the market outcome if a market for atmospheric chemistry could be created. A nice fat tax on the use of petroleum and coal would do the trick. Equivalently, you can pay subsidies to people who use alternative energy sources.

The alternative is to wait around until entrepreneurs come up with energy sources that are not damaging to the atmosphere and are cheaper than petroleum. But that does not seem to be
happening fast enough to keep us from getting to what appears
to be the looming tipping point. R&D in energy has focused primarily on rendering new sources of petroleum financially feasible.

At this point, we’re going to need a “Manhattan Project” type effort to meaningfully address the issue.

Regarding the polar bears a blog I frequent has a resident AGW sceptic/ anti-environmentalist who just recently highlighted that article.

Another sceptic popped up with a site of researchers showing while some populations were going down and some up most appeared stable, therefore no impact from GW and we don’t have to worry.

A little more digging had those same researchers saying more research should be done, that hunting shouldn’t just be done on locals knowledge- increase in local bear numbers around settlements due to starvation- and

“The Group concluded that the IUCN Red List classification of the polar bear should be upgraded from Least Concern to Vulnerable based on the likelihood of an overall decline in the size of the total population of more than 30% within the next 35 to 50 years. The principal cause of this decline is climatic warming and its consequent negative affects on the sea ice habitat of polar bears. In some areas, contaminants may have an additive negative influence.”
Read the PBSG latest press release 14th meeting of PBSG in Seattle, USA 2005

Our resident sceptic thinks you can dismiss the recommendations of the researchers, only the current raw data can be used as the researchers want a job for life studying an endangered species!

Well why not he dismisses the work of climatologists.

You don’t know what you are talking about, a detailed google around will show you are all wrong; guess you must be disappointed that those years of study and work amounts to nothing.

#30: “You’re saying that we should change the earth faster to reduce barriers to new speciation? Are we talking about the needs of potential species?”

I’m saying why worry about one or two species when many many more could benefit in a warming scenario. Polar bears will probably be around as long as seals are anyhow. Global climate, as far as I can tell, is far more up to Mother Nature than to us humans.

#37: I don’t forsee a “severe economic dislocation” based on global warming. A warmer, wetter, CO2-fertilized future sounds like good news, more productive crops, less crop-killing frosts, longer growing seasons etc… See my links above for more. If your “take action now” means handing over more power and money to politicians, then I fail to see how that is going to lead to less government intervention in the lives of citizens. Even if you are right, with my approach the slide to totalitarianism starts later and takes longer.

Actually I’m concerned that the true aims of the alarmist community are revealed by their proposed “solutions” to Global Warming which all involve putting more power in the hands of politicians and bureaucrats… [cut]

I have wondered for a long time, what the decrease of the latitudinal temperature gradient (due to the arctic warming faster than the rest) might mean for atmospheric circulation. One could make some general (theoretical) condsiderations:

– in principle the existing circulation system is the result of the temperature difference between polar and tropical regions (due to the different amount of incoming radiation), of earth’s rotation speed (if the speed was much lower, circulation system would probably be much less chaotic) and also of the land mass / ocean distribution and huge mountain regions (like the Rocky Mountains). Much of the rest is internal variation.
– the pattern of the polar front (as the border between cold air in the north and warm air in the south) is formed in a way that allows the “necessary” latitudinal heat transport. This transport is more effective, if the flow pattern is more meridional, i.e. with strong waves, and most effective if there is decoupling of cold (or warm) air masses drifting to the south (or north, resp.)., because these are rotating systems which are not deflected by the Coriolis force. The latitudinal heat transport happens through the dynamics of the circulation system, because it has to overcome the Coriolis force somehow.
– Now, one could suggest that if the latitudinal temperature gradient decreases, the dynamics of the circulation system could decrease as well. That would in general mean more zonal than meridional flow patterns and/or more stable circulation patterns.

Do you know of any such considerations or model results which point into such a direction?
Of course there are many other patterns which influence the circulation patterns (AO/NAO, ENSO, etc.), but this might be a general underlying trend in the long-term.

More stable flow patterns could mean more extreme weather – not only concerning temperature, but also other extremes like precipitation (if persisting over the same region) or even storms. Zonal flow patterns have higher wind speeds in general, so high wind speeds could be more frequent despite a general decrease due to the decrease of the temperature gradient.

I have a general impression, that circulation patterns are more stable today than 10, 20 years ago and have become more zonal, especially in winter. This is subjective, and I’m not sure if it is really true (it’s not easy to find an objective parameter to describe such pattern changes…).

Well, what do you think?

[Response: I can make some similarly general points (maybe we can get Isaac to chime in?). I think in general you are correct. The key temperature gradient is not the equator to pole, but more sub-tropics to sub-polar which sets up the conditions needed for baroclinic instability. The winter circulation patterns are more coherent than the summer and there has been a long term trend to more zonal flow (NAO/AO indices), though it is not a strong a trend as it appeared back in the late 90s. However the link between the temperature gradient and the zonality of the flow is not straightforward or well known. In some model experiments, it is the upper atmosphere gradients that have a big influence, in others, it is changes in planetary wave activity. In the IPCC AR4 runs, there is a robust model tendency towards more zonal flow (see here) for what that’s worth. However I don’t follow your conclusion that more zonal flow implies more extremes. As we have seen this month, winter extremes in temperature are associated with large displacements of the jet stream (i.e. extremely a-zonal flow), and the paper by Thompson and Wallace (Science, 2001) showed that more quantitatively (for instance, I think I recall that temperature extremes in Paris are 5 times more likely with negative NAO than with with positive NAO). With respect to individual storms, there is some indication of a slight deepening of the low pressure with time, but I am unsure why that is thought to have occured. – gavin]

Re #16 and #19: I also noticed the high Arctic temperatures. There have been record high temperatures in Svalbard [north of Norway] this winter and it seems the ice isn’t coming as far south as normal. There’s recently been a lot of attention paid to record low minimum extents of the Arctic sea-ice in September, but less attention to what is happening to maximum ice extents in March.

Why is this? Has less been changing? Is there less data? Or have I just missed it?

Re #41: mid-latitude circulation. Modelling studies generally show a weaker storm track [fewer cyclonic systems] when the meridional gradient weakens under climate change. However, there are some suggestions that the distribution of storms may change with their being more strong storms [measured by minimum central pressure], possibly due to the extra energy available due to the warmer oceans.

What the hell happened to winter?
According to the calendar today is February 3rd, 2006 yet when I stepped outside this morning it felt and looked more like late March or mid April. There isn't a spec of snow anywhere outside of downtown Detroit at the Winter Blast celebration tha…

The person who has posted this obviously dimsisses all the studies which show that crops will be negatively affected by GW in future. Here, for example a press release about a conference on the subject organised by the Royal Society: http://www.royalsoc.ac.uk/news.asp?year=&id=3084

Worryingly, global crop production was on a downward spiral for three years before 2004. In 2004, there was a bumper harvest because the main growing areas in the US were not too warm and not too dry that summer (something forecast to become much less common). Down again in 2005, with losses primarily attributed to extreme weather (very hog summer, drought in many growing areas). For week-to-week worrying news you only need to look here http://www.metoffice.com/cgi-bin/newsid . January’s news included severe losses to US winter crop because of anomalous warmth and drought, 50% reduction in grain harvests in Texas last year, disastrous spring harvest forecast there (meaning a total loss of 1.5 billion dollars just in Texas). Not to mention eastern Africa, much of southern Africa, torrential rains destroying part of India’s cotton harvest, etc.

Gavin – thanks for your response.
Of course the temperature gradient is mainly along the polar front. But this also is a result of the pattern produced by the general north-south gradient in combination with earth rotation. However, this is a minor point.

Maybe I wasn’t clear enough. I mentioned two different possible reactions, i.e. circulation getting more stable or getting more zonal.
I thought of the circulation getting more stable, which could possibly lead to more extremes, e.g.
– displacement of the jet stream (or polar front) in the same pattern over several months, which of course produces strong temperature anomalies as those discussed here, or which produced the summer heat wave 2003 over Europe
– in the scale of weeks stable flow can lead to big amount of snowfall (like 1999 in the Alps) or to heavy rainfall events. Stable flow patterns can lead to repetition of the same events in short time, like the floods in Europe a few years ago.
– stable flow might ev. also favour the development of very heavy midlatitude storms like Lothar 1999 in Europe
That’s what I meant.

Nanny, you are saying that our current course will provide a warmer wetter more productive world that can support higher biodiversity, and therefore we should stay the course.

There will be some extinctions, but many more new species will appear.

Are you aware that in the geologic record, the “rapid speciation” periods after mass extinctions take millions of years?

Sure, a new species can form instantaneously. An adapted species, having accumulated myriad helpful changes to its DNA, does not.

But let’s say that we’re willing to wait millions of years to see the benefits to biodiversity from our elevated CO2 levels. How are we going to maintain these elevated levels of CO2 for millions of years after the oil runs out?

> 13, 27(not 26), 43 — outgoing infrared, question for lay reader
I appreciate the pointer Stephen gave; Hans, you know how to read those data sets, I don’t; can either of you say a bit more to explain them? I confess visual aids always help me, if someone’s made them.

I can imagine that both could be true — blocking more outgoing infrared as CO2 increases, yet still measuring more from the satellite looking down. If the planet’s warming faster than the IR opacity increases, wouldn’t that be the result? I’m probably asking you all to oversimplify this for me.